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Code Issues Releases Wiki Activity

Additional search.cpp cleanup

Browse source 
Changed FutilityMarginsMatrix dimensions to be a power of two
so that compiler can produce a faster accessing code.

Introduced print_pv_info() to remove some redundant code in
root_search()

Remaining stuff is triviality and documentation tweaks.

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This commit is contained in:
Marco Costalba 2010-03-05 11:55:27 +01:00
parent 0f50f10327
commit a303bde26c
1 changed files with 126 additions and 138 deletions
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250
src/search.cpp
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@ -165,7 +165,7 @@ namespace {
const Depth RazorDepth = 4 * OnePly; const Depth RazorDepth = 4 * OnePly;
// Dynamic razoring margin based on depth // Dynamic razoring margin based on depth
inline Value razor_margin(Depth d) { return Value(0x200 + 0x10 * d); } inline Value razor_margin(Depth d) { return Value(0x200 + 0x10 * int(d)); }
// Step 8. Null move search with verification search // Step 8. Null move search with verification search
@ -182,14 +182,13 @@ namespace {
const Depth IIDDepthAtPVNodes = 5 * OnePly; const Depth IIDDepthAtPVNodes = 5 * OnePly;
const Depth IIDDepthAtNonPVNodes = 8 * OnePly; const Depth IIDDepthAtNonPVNodes = 8 * OnePly;
// Internal iterative deepening margin. At Non-PV nodes // At Non-PV nodes we do an internal iterative deepening search
// we do an internal iterative deepening // when the static evaluation is at most IIDMargin below beta.
// search when the static evaluation is at most IIDMargin below beta.
const Value IIDMargin = Value(0x100); const Value IIDMargin = Value(0x100);
// Step 11. Decide the new search depth // Step 11. Decide the new search depth
// Extensions. Configurable UCI options. // Extensions. Configurable UCI options
// Array index 0 is used at non-PV nodes, index 1 at PV nodes. // Array index 0 is used at non-PV nodes, index 1 at PV nodes.
Depth CheckExtension[2], SingleEvasionExtension[2], PawnPushTo7thExtension[2]; Depth CheckExtension[2], SingleEvasionExtension[2], PawnPushTo7thExtension[2];
Depth PassedPawnExtension[2], PawnEndgameExtension[2], MateThreatExtension[2]; Depth PassedPawnExtension[2], PawnEndgameExtension[2], MateThreatExtension[2];
@ -208,11 +207,11 @@ namespace {
const Value FutilityMarginQS = Value(0x80); const Value FutilityMarginQS = Value(0x80);
// Futility lookup tables (initialized at startup) and their getter functions // Futility lookup tables (initialized at startup) and their getter functions
int32_t FutilityMarginsMatrix[14][64]; // [depth][moveNumber] int32_t FutilityMarginsMatrix[16][64]; // [depth][moveNumber]
int FutilityMoveCountArray[32]; // [depth] int FutilityMoveCountArray[32]; // [depth]
inline Value futility_margin(Depth d, int mn) { return Value(d < 7*OnePly ? FutilityMarginsMatrix[Max(d, 0)][Min(mn, 63)] : 2 * VALUE_INFINITE); } inline Value futility_margin(Depth d, int mn) { return Value(d < 7 * OnePly ? FutilityMarginsMatrix[Max(d, 0)][Min(mn, 63)] : 2 * VALUE_INFINITE); }
inline int futility_move_count(Depth d) { return d < 16*OnePly ? FutilityMoveCountArray[d] : 512; } inline int futility_move_count(Depth d) { return d < 16 * OnePly ? FutilityMoveCountArray[d] : 512; }
// Step 14. Reduced search // Step 14. Reduced search
@ -223,7 +222,7 @@ namespace {
inline Depth pv_reduction(Depth d, int mn) { return (Depth) PVReductionMatrix[Min(d / 2, 63)][Min(mn, 63)]; } inline Depth pv_reduction(Depth d, int mn) { return (Depth) PVReductionMatrix[Min(d / 2, 63)][Min(mn, 63)]; }
inline Depth nonpv_reduction(Depth d, int mn) { return (Depth) NonPVReductionMatrix[Min(d / 2, 63)][Min(mn, 63)]; } inline Depth nonpv_reduction(Depth d, int mn) { return (Depth) NonPVReductionMatrix[Min(d / 2, 63)][Min(mn, 63)]; }
// Step. Common adjustments // Common adjustments
// Search depth at iteration 1 // Search depth at iteration 1
const Depth InitialDepth = OnePly; const Depth InitialDepth = OnePly;
@ -241,7 +240,7 @@ namespace {
/// Global variables /// Global variables
// Iteration counters // Iteration counter
int Iteration; int Iteration;
// Scores and number of times the best move changed for each iteration // Scores and number of times the best move changed for each iteration
@ -255,13 +254,10 @@ namespace {
int MultiPV; int MultiPV;
// Time managment variables // Time managment variables
int RootMoveNumber; int RootMoveNumber, SearchStartTime, MaxNodes, MaxDepth;
int SearchStartTime;
int MaxNodes, MaxDepth;
int MaxSearchTime, AbsoluteMaxSearchTime, ExtraSearchTime, ExactMaxTime; int MaxSearchTime, AbsoluteMaxSearchTime, ExtraSearchTime, ExactMaxTime;
bool UseTimeManagement, InfiniteSearch, PonderSearch, StopOnPonderhit; bool UseTimeManagement, InfiniteSearch, PonderSearch, StopOnPonderhit;
bool AbortSearch, Quit; bool AbortSearch, Quit, AspirationFailLow;
bool AspirationFailLow;
// Show current line? // Show current line?
bool ShowCurrentLine; bool ShowCurrentLine;
@ -270,20 +266,20 @@ namespace {
bool UseLogFile; bool UseLogFile;
std::ofstream LogFile; std::ofstream LogFile;
// MP related variables // Multi-threads related variables
Depth MinimumSplitDepth; Depth MinimumSplitDepth;
int MaxThreadsPerSplitPoint; int MaxThreadsPerSplitPoint;
ThreadsManager TM; ThreadsManager TM;
// Node counters, used only by thread[0] but try to keep in different // Node counters, used only by thread[0] but try to keep in different cache
// cache lines (64 bytes each) from the heavy SMP read accessed variables. // lines (64 bytes each) from the heavy multi-thread read accessed variables.
int NodesSincePoll; int NodesSincePoll;
int NodesBetweenPolls = 30000; int NodesBetweenPolls = 30000;
// History table // History table
History H; History H;
/// Functions /// Local functions
Value id_loop(const Position& pos, Move searchMoves[]); Value id_loop(const Position& pos, Move searchMoves[]);
Value root_search(Position& pos, SearchStack ss[], RootMoveList& rml, Value& oldAlpha, Value& beta); Value root_search(Position& pos, SearchStack ss[], RootMoveList& rml, Value& oldAlpha, Value& beta);
@ -313,6 +309,7 @@ namespace {
void ponderhit(); void ponderhit();
void wait_for_stop_or_ponderhit(); void wait_for_stop_or_ponderhit();
void init_ss_array(SearchStack ss[]); void init_ss_array(SearchStack ss[]);
void print_pv_info(const Position& pos, SearchStack ss[], Value alpha, Value beta, Value value);
#if !defined(_MSC_VER) #if !defined(_MSC_VER)
void *init_thread(void *threadID); void *init_thread(void *threadID);
@ -340,9 +337,10 @@ int64_t nodes_searched() { return TM.nodes_searched(); }
int perft(Position& pos, Depth depth) int perft(Position& pos, Depth depth)
{ {
StateInfo st;
Move move; Move move;
int sum = 0; int sum = 0;
MovePicker mp = MovePicker(pos, MOVE_NONE, depth, H); MovePicker mp(pos, MOVE_NONE, depth, H);
// If we are at the last ply we don't need to do and undo // If we are at the last ply we don't need to do and undo
// the moves, just to count them. // the moves, just to count them.
@ -356,7 +354,6 @@ int perft(Position& pos, Depth depth)
CheckInfo ci(pos); CheckInfo ci(pos);
while ((move = mp.get_next_move()) != MOVE_NONE) while ((move = mp.get_next_move()) != MOVE_NONE)
{ {
StateInfo st;
pos.do_move(move, st, ci, pos.move_is_check(move, ci)); pos.do_move(move, st, ci, pos.move_is_check(move, ci));
sum += perft(pos, depth - OnePly); sum += perft(pos, depth - OnePly);
pos.undo_move(move); pos.undo_move(move);
@ -375,9 +372,9 @@ bool think(const Position& pos, bool infinite, bool ponder, int side_to_move,
int maxNodes, int maxTime, Move searchMoves[]) { int maxNodes, int maxTime, Move searchMoves[]) {
// Initialize global search variables // Initialize global search variables
StopOnPonderhit = AbortSearch = Quit = false; StopOnPonderhit = AbortSearch = Quit = AspirationFailLow = false;
AspirationFailLow = false;
NodesSincePoll = 0; NodesSincePoll = 0;
TM.resetNodeCounters();
SearchStartTime = get_system_time(); SearchStartTime = get_system_time();
ExactMaxTime = maxTime; ExactMaxTime = maxTime;
MaxDepth = maxDepth; MaxDepth = maxDepth;
@ -389,11 +386,10 @@ bool think(const Position& pos, bool infinite, bool ponder, int side_to_move,
// Look for a book move, only during games, not tests // Look for a book move, only during games, not tests
if (UseTimeManagement && get_option_value_bool("OwnBook")) if (UseTimeManagement && get_option_value_bool("OwnBook"))
{ {
Move bookMove;
if (get_option_value_string("Book File") != OpeningBook.file_name()) if (get_option_value_string("Book File") != OpeningBook.file_name())
OpeningBook.open(get_option_value_string("Book File")); OpeningBook.open(get_option_value_string("Book File"));
bookMove = OpeningBook.get_move(pos); Move bookMove = OpeningBook.get_move(pos);
if (bookMove != MOVE_NONE) if (bookMove != MOVE_NONE)
{ {
if (PonderSearch) if (PonderSearch)
@ -404,45 +400,37 @@ bool think(const Position& pos, bool infinite, bool ponder, int side_to_move,
} }
} }
TM.resetNodeCounters(); // Reset loseOnTime flag at the beginning of a new game
if (button_was_pressed("New Game")) if (button_was_pressed("New Game"))
loseOnTime = false; // Reset at the beginning of a new game loseOnTime = false;
// Read UCI option values // Read UCI option values
TT.set_size(get_option_value_int("Hash")); TT.set_size(get_option_value_int("Hash"));
if (button_was_pressed("Clear Hash")) if (button_was_pressed("Clear Hash"))
TT.clear(); TT.clear();
bool PonderingEnabled = get_option_value_bool("Ponder");
MultiPV = get_option_value_int("MultiPV");
CheckExtension[1] = Depth(get_option_value_int("Check Extension (PV nodes)")); CheckExtension[1] = Depth(get_option_value_int("Check Extension (PV nodes)"));
CheckExtension[0] = Depth(get_option_value_int("Check Extension (non-PV nodes)")); CheckExtension[0] = Depth(get_option_value_int("Check Extension (non-PV nodes)"));
SingleEvasionExtension[1] = Depth(get_option_value_int("Single Evasion Extension (PV nodes)")); SingleEvasionExtension[1] = Depth(get_option_value_int("Single Evasion Extension (PV nodes)"));
SingleEvasionExtension[0] = Depth(get_option_value_int("Single Evasion Extension (non-PV nodes)")); SingleEvasionExtension[0] = Depth(get_option_value_int("Single Evasion Extension (non-PV nodes)"));
PawnPushTo7thExtension[1] = Depth(get_option_value_int("Pawn Push to 7th Extension (PV nodes)")); PawnPushTo7thExtension[1] = Depth(get_option_value_int("Pawn Push to 7th Extension (PV nodes)"));
PawnPushTo7thExtension[0] = Depth(get_option_value_int("Pawn Push to 7th Extension (non-PV nodes)")); PawnPushTo7thExtension[0] = Depth(get_option_value_int("Pawn Push to 7th Extension (non-PV nodes)"));
PassedPawnExtension[1] = Depth(get_option_value_int("Passed Pawn Extension (PV nodes)")); PassedPawnExtension[1] = Depth(get_option_value_int("Passed Pawn Extension (PV nodes)"));
PassedPawnExtension[0] = Depth(get_option_value_int("Passed Pawn Extension (non-PV nodes)")); PassedPawnExtension[0] = Depth(get_option_value_int("Passed Pawn Extension (non-PV nodes)"));
PawnEndgameExtension[1] = Depth(get_option_value_int("Pawn Endgame Extension (PV nodes)")); PawnEndgameExtension[1] = Depth(get_option_value_int("Pawn Endgame Extension (PV nodes)"));
PawnEndgameExtension[0] = Depth(get_option_value_int("Pawn Endgame Extension (non-PV nodes)")); PawnEndgameExtension[0] = Depth(get_option_value_int("Pawn Endgame Extension (non-PV nodes)"));
MateThreatExtension[1] = Depth(get_option_value_int("Mate Threat Extension (PV nodes)")); MateThreatExtension[1] = Depth(get_option_value_int("Mate Threat Extension (PV nodes)"));
MateThreatExtension[0] = Depth(get_option_value_int("Mate Threat Extension (non-PV nodes)")); MateThreatExtension[0] = Depth(get_option_value_int("Mate Threat Extension (non-PV nodes)"));
Chess960 = get_option_value_bool("UCI_Chess960");
ShowCurrentLine = get_option_value_bool("UCI_ShowCurrLine");
UseLogFile = get_option_value_bool("Use Search Log");
if (UseLogFile)
LogFile.open(get_option_value_string("Search Log Filename").c_str(), std::ios::out | std::ios::app);
MinimumSplitDepth = get_option_value_int("Minimum Split Depth") * OnePly; MinimumSplitDepth = get_option_value_int("Minimum Split Depth") * OnePly;
MaxThreadsPerSplitPoint = get_option_value_int("Maximum Number of Threads per Split Point"); MaxThreadsPerSplitPoint = get_option_value_int("Maximum Number of Threads per Split Point");
ShowCurrentLine = get_option_value_bool("UCI_ShowCurrLine");
MultiPV = get_option_value_int("MultiPV");
Chess960 = get_option_value_bool("UCI_Chess960");
UseLogFile = get_option_value_bool("Use Search Log");
if (UseLogFile)
LogFile.open(get_option_value_string("Search Log Filename").c_str(), std::ios::out | std::ios::app);
read_weights(pos.side_to_move()); read_weights(pos.side_to_move());
@ -493,14 +481,15 @@ bool think(const Position& pos, bool infinite, bool ponder, int side_to_move,
} }
} }
if (PonderingEnabled) if (get_option_value_bool("Ponder"))
{ {
MaxSearchTime += MaxSearchTime / 4; MaxSearchTime += MaxSearchTime / 4;
MaxSearchTime = Min(MaxSearchTime, AbsoluteMaxSearchTime); MaxSearchTime = Min(MaxSearchTime, AbsoluteMaxSearchTime);
} }
} }
// Set best NodesBetweenPolls interval // Set best NodesBetweenPolls interval to avoid lagging under
// heavy time pressure.
if (MaxNodes) if (MaxNodes)
NodesBetweenPolls = Min(MaxNodes, 30000); NodesBetweenPolls = Min(MaxNodes, 30000);
else if (myTime && myTime < 1000) else if (myTime && myTime < 1000)
@ -510,7 +499,7 @@ bool think(const Position& pos, bool infinite, bool ponder, int side_to_move,
else else
NodesBetweenPolls = 30000; NodesBetweenPolls = 30000;
// Write information to search log file // Write search information to log file
if (UseLogFile) if (UseLogFile)
LogFile << "Searching: " << pos.to_fen() << endl LogFile << "Searching: " << pos.to_fen() << endl
<< "infinite: " << infinite << "infinite: " << infinite
@ -519,7 +508,7 @@ bool think(const Position& pos, bool infinite, bool ponder, int side_to_move,
<< " increment: " << myIncrement << " increment: " << myIncrement
<< " moves to go: " << movesToGo << endl; << " moves to go: " << movesToGo << endl;
// LSN filtering. Used only for developing purpose. Disabled by default. // LSN filtering. Used only for developing purposes, disabled by default
if ( UseLSNFiltering if ( UseLSNFiltering
&& loseOnTime) && loseOnTime)
{ {
@ -574,10 +563,11 @@ void init_search() {
} }
// Init futility margins array // Init futility margins array
for (int i = 0; i < 14; i++) // i == depth (OnePly = 2) for (int i = 0; i < 16; i++) // i == depth (OnePly = 2)
for (int j = 0; j < 64; j++) // j == moveNumber for (int j = 0; j < 64; j++) // j == moveNumber
{ {
FutilityMarginsMatrix[i][j] = (i < 2 ? 0 : 112 * bitScanReverse32(i * i / 2)) - 8 * j; // FIXME: test using log instead of BSR // FIXME: test using log instead of BSR
FutilityMarginsMatrix[i][j] = (i < 2 ? 0 : 112 * bitScanReverse32(i * i / 2)) - 8 * j;
} }
// Init futility move count array // Init futility move count array
@ -614,8 +604,10 @@ namespace {
Position p(pos); Position p(pos);
SearchStack ss[PLY_MAX_PLUS_2]; SearchStack ss[PLY_MAX_PLUS_2];
Move EasyMove = MOVE_NONE;
Value value, alpha = -VALUE_INFINITE, beta = VALUE_INFINITE;
// searchMoves are verified, copied, scored and sorted // Moves to search are verified, copied, scored and sorted
RootMoveList rml(p, searchMoves); RootMoveList rml(p, searchMoves);
// Handle special case of searching on a mate/stale position // Handle special case of searching on a mate/stale position
@ -624,12 +616,13 @@ namespace {
if (PonderSearch) if (PonderSearch)
wait_for_stop_or_ponderhit(); wait_for_stop_or_ponderhit();
return pos.is_check()? -VALUE_MATE : VALUE_DRAW; return pos.is_check() ? -VALUE_MATE : VALUE_DRAW;
} }
// Print RootMoveList c'tor startup scoring to the standard output, // Print RootMoveList startup scoring to the standard output,
// so that we print information also for iteration 1. // so to output information also for iteration 1.
cout << "info depth " << 1 << "\ninfo depth " << 1 cout << "info depth " << 1
<< "\ninfo depth " << 1
<< " score " << value_to_string(rml.get_move_score(0)) << " score " << value_to_string(rml.get_move_score(0))
<< " time " << current_search_time() << " time " << current_search_time()
<< " nodes " << TM.nodes_searched() << " nodes " << TM.nodes_searched()
@ -644,7 +637,6 @@ namespace {
Iteration = 1; Iteration = 1;
// Is one move significantly better than others after initial scoring ? // Is one move significantly better than others after initial scoring ?
Move EasyMove = MOVE_NONE;
if ( rml.move_count() == 1 if ( rml.move_count() == 1
|| rml.get_move_score(0) > rml.get_move_score(1) + EasyMoveMargin) || rml.get_move_score(0) > rml.get_move_score(1) + EasyMoveMargin)
EasyMove = rml.get_move(0); EasyMove = rml.get_move(0);
@ -661,9 +653,7 @@ namespace {
cout << "info depth " << Iteration << endl; cout << "info depth " << Iteration << endl;
// Calculate dynamic search window based on previous iterations // Calculate dynamic aspiration window based on previous iterations
Value alpha, beta;
if (MultiPV == 1 && Iteration >= 6 && abs(ValueByIteration[Iteration - 1]) < VALUE_KNOWN_WIN) if (MultiPV == 1 && Iteration >= 6 && abs(ValueByIteration[Iteration - 1]) < VALUE_KNOWN_WIN)
{ {
int prevDelta1 = ValueByIteration[Iteration - 1] - ValueByIteration[Iteration - 2]; int prevDelta1 = ValueByIteration[Iteration - 1] - ValueByIteration[Iteration - 2];
@ -675,14 +665,9 @@ namespace {
alpha = Max(ValueByIteration[Iteration - 1] - AspirationDelta, -VALUE_INFINITE); alpha = Max(ValueByIteration[Iteration - 1] - AspirationDelta, -VALUE_INFINITE);
beta = Min(ValueByIteration[Iteration - 1] + AspirationDelta, VALUE_INFINITE); beta = Min(ValueByIteration[Iteration - 1] + AspirationDelta, VALUE_INFINITE);
} }
else
{
alpha = - VALUE_INFINITE;
beta = VALUE_INFINITE;
}
// Search to the current depth // Search to the current depth
Value value = root_search(p, ss, rml, alpha, beta); value = root_search(p, ss, rml, alpha, beta);
// Write PV to transposition table, in case the relevant entries have // Write PV to transposition table, in case the relevant entries have
// been overwritten during the search. // been overwritten during the search.
@ -694,7 +679,7 @@ namespace {
//Save info about search result //Save info about search result
ValueByIteration[Iteration] = value; ValueByIteration[Iteration] = value;
// Drop the easy move if it differs from the new best move // Drop the easy move if differs from the new best move
if (ss[0].pv[0] != EasyMove) if (ss[0].pv[0] != EasyMove)
EasyMove = MOVE_NONE; EasyMove = MOVE_NONE;
@ -714,7 +699,7 @@ namespace {
&& abs(ValueByIteration[Iteration-1]) >= abs(VALUE_MATE) - 100) && abs(ValueByIteration[Iteration-1]) >= abs(VALUE_MATE) - 100)
stopSearch = true; stopSearch = true;
// Stop search early if one move seems to be much better than the rest // Stop search early if one move seems to be much better than the others
int64_t nodes = TM.nodes_searched(); int64_t nodes = TM.nodes_searched();
if ( Iteration >= 8 if ( Iteration >= 8
&& EasyMove == ss[0].pv[0] && EasyMove == ss[0].pv[0]
@ -737,10 +722,10 @@ namespace {
if (stopSearch) if (stopSearch)
{ {
if (!PonderSearch) if (PonderSearch)
break;
else
StopOnPonderhit = true; StopOnPonderhit = true;
else
break;
} }
} }
@ -767,7 +752,11 @@ namespace {
ss[0].pv[0] = rml.get_move(0); ss[0].pv[0] = rml.get_move(0);
ss[0].pv[1] = MOVE_NONE; ss[0].pv[1] = MOVE_NONE;
} }
assert(ss[0].pv[0] != MOVE_NONE);
cout << "bestmove " << ss[0].pv[0]; cout << "bestmove " << ss[0].pv[0];
if (ss[0].pv[1] != MOVE_NONE) if (ss[0].pv[1] != MOVE_NONE)
cout << " ponder " << ss[0].pv[1]; cout << " ponder " << ss[0].pv[1];
@ -787,7 +776,9 @@ namespace {
StateInfo st; StateInfo st;
p.do_move(ss[0].pv[0], st); p.do_move(ss[0].pv[0], st);
LogFile << "\nPonder move: " << move_to_san(p, ss[0].pv[1]) << endl; LogFile << "\nPonder move: "
<< move_to_san(p, ss[0].pv[1]) // Works also with MOVE_NONE
<< endl;
} }
return rml.get_move_score(0); return rml.get_move_score(0);
} }
@ -795,28 +786,28 @@ namespace {
// root_search() is the function which searches the root node. It is // root_search() is the function which searches the root node. It is
// similar to search_pv except that it uses a different move ordering // similar to search_pv except that it uses a different move ordering
// scheme and prints some information to the standard output. // scheme, prints some information to the standard output and handles
// the fail low/high loops.
Value root_search(Position& pos, SearchStack ss[], RootMoveList& rml, Value& oldAlpha, Value& beta) { Value root_search(Position& pos, SearchStack ss[], RootMoveList& rml, Value& oldAlpha, Value& beta) {
EvalInfo ei;
StateInfo st;
int64_t nodes; int64_t nodes;
Move move; Move move;
StateInfo st;
Depth depth, ext, newDepth; Depth depth, ext, newDepth;
Value value; Value value, alpha;
CheckInfo ci(pos); bool isCheck, moveIsCheck, captureOrPromotion, dangerous;
int researchCount = 0; int researchCount = 0;
bool moveIsCheck, captureOrPromotion, dangerous; CheckInfo ci(pos);
Value alpha = oldAlpha; alpha = oldAlpha;
bool isCheck = pos.is_check(); isCheck = pos.is_check();
// Evaluate the position statically // Evaluate the position statically
EvalInfo ei;
ss[0].eval = !isCheck ? evaluate(pos, ei, 0) : VALUE_NONE; ss[0].eval = !isCheck ? evaluate(pos, ei, 0) : VALUE_NONE;
while (1) // Fail low loop while (1) // Fail low loop
{ {
// Loop through all the moves in the root move list // Loop through all the moves in the root move list
for (int i = 0; i < rml.move_count() && !AbortSearch; i++) for (int i = 0; i < rml.move_count() && !AbortSearch; i++)
{ {
@ -829,6 +820,7 @@ namespace {
continue; continue;
} }
// This is used by time management and starts from 1
RootMoveNumber = i + 1; RootMoveNumber = i + 1;
// Save the current node count before the move is searched // Save the current node count before the move is searched
@ -852,11 +844,11 @@ namespace {
ext = extension(pos, move, true, captureOrPromotion, moveIsCheck, false, false, &dangerous); ext = extension(pos, move, true, captureOrPromotion, moveIsCheck, false, false, &dangerous);
newDepth = depth + ext; newDepth = depth + ext;
// Reset value before the search
value = - VALUE_INFINITE; value = - VALUE_INFINITE;
while (1) // Fail high loop while (1) // Fail high loop
{ {
// Make the move, and search it // Make the move, and search it
pos.do_move(move, st, ci, moveIsCheck); pos.do_move(move, st, ci, moveIsCheck);
@ -866,6 +858,7 @@ namespace {
if (MultiPV > 1) if (MultiPV > 1)
alpha = -VALUE_INFINITE; alpha = -VALUE_INFINITE;
// Full depth PV search, done on first move or after a fail high
value = -search_pv(pos, ss, -beta, -alpha, newDepth, 1, 0); value = -search_pv(pos, ss, -beta, -alpha, newDepth, 1, 0);
} }
else else
@ -874,14 +867,15 @@ namespace {
// if the move fails high will be re-searched at full depth. // if the move fails high will be re-searched at full depth.
bool doFullDepthSearch = true; bool doFullDepthSearch = true;
if ( depth >= 3*OnePly // FIXME was newDepth if ( depth >= 3 * OnePly // FIXME was newDepth
&& !dangerous && !dangerous
&& !captureOrPromotion && !captureOrPromotion
&& !move_is_castle(move)) && !move_is_castle(move))
{ {
ss[0].reduction = pv_reduction(depth, RootMoveNumber - MultiPV + 1); ss[0].reduction = pv_reduction(depth, i - MultiPV + 2);
if (ss[0].reduction) if (ss[0].reduction)
{ {
// Reduced depth non-pv search using alpha as upperbound
value = -search(pos, ss, -alpha, newDepth-ss[0].reduction, 1, true, 0); value = -search(pos, ss, -alpha, newDepth-ss[0].reduction, 1, true, 0);
doFullDepthSearch = (value > alpha); doFullDepthSearch = (value > alpha);
} }
@ -889,9 +883,12 @@ namespace {
if (doFullDepthSearch) if (doFullDepthSearch)
{ {
// Full depth non-pv search using alpha as upperbound
ss[0].reduction = Depth(0); ss[0].reduction = Depth(0);
value = -search(pos, ss, -alpha, newDepth, 1, true, 0); value = -search(pos, ss, -alpha, newDepth, 1, true, 0);
// If we are above alpha then research at same depth but as PV
// to get a correct score or eventually a fail high above beta.
if (value > alpha) if (value > alpha)
value = -search_pv(pos, ss, -beta, -alpha, newDepth, 1, 0); value = -search_pv(pos, ss, -beta, -alpha, newDepth, 1, 0);
} }
@ -903,36 +900,15 @@ namespace {
if (AbortSearch || value < beta) if (AbortSearch || value < beta)
break; break;
// We are failing high and going to do a research. It's important to update score // We are failing high and going to do a research. It's important to update
// before research in case we run out of time while researching. // the score before research in case we run out of time while researching.
rml.set_move_score(i, value); rml.set_move_score(i, value);
update_pv(ss, 0); update_pv(ss, 0);
TT.extract_pv(pos, ss[0].pv, PLY_MAX); TT.extract_pv(pos, ss[0].pv, PLY_MAX);
rml.set_move_pv(i, ss[0].pv); rml.set_move_pv(i, ss[0].pv);
// Print search information to the standard output // Print information to the standard output
cout << "info depth " << Iteration print_pv_info(pos, ss, alpha, beta, value);
<< " score " << value_to_string(value)
<< ((value >= beta) ? " lowerbound" :
((value <= alpha)? " upperbound" : ""))
<< " time " << current_search_time()
<< " nodes " << TM.nodes_searched()
<< " nps " << nps()
<< " pv ";
for (int j = 0; ss[0].pv[j] != MOVE_NONE && j < PLY_MAX; j++)
cout << ss[0].pv[j] << " ";
cout << endl;
if (UseLogFile)
{
ValueType type = (value >= beta ? VALUE_TYPE_LOWER
: (value <= alpha ? VALUE_TYPE_UPPER : VALUE_TYPE_EXACT));
LogFile << pretty_pv(pos, current_search_time(), Iteration,
TM.nodes_searched(), value, type, ss[0].pv) << endl;
}
// Prepare for a research after a fail high, each time with a wider window // Prepare for a research after a fail high, each time with a wider window
researchCount++; researchCount++;
@ -977,29 +953,11 @@ namespace {
if (i > 0) if (i > 0)
BestMoveChangesByIteration[Iteration]++; BestMoveChangesByIteration[Iteration]++;
// Print search information to the standard output // Print information to the standard output
cout << "info depth " << Iteration print_pv_info(pos, ss, alpha, beta, value);
<< " score " << value_to_string(value)
<< ((value >= beta) ? " lowerbound" :
((value <= alpha)? " upperbound" : ""))
<< " time " << current_search_time()
<< " nodes " << TM.nodes_searched()
<< " nps " << nps()
<< " pv ";
for (int j = 0; ss[0].pv[j] != MOVE_NONE && j < PLY_MAX; j++) // Raise alpha to setup proper non-pv search upper bound, note
cout << ss[0].pv[j] << " "; // that we can end up with alpha >= beta and so get a fail high.
cout << endl;
if (UseLogFile)
{
ValueType type = (value >= beta ? VALUE_TYPE_LOWER
: (value <= alpha ? VALUE_TYPE_UPPER : VALUE_TYPE_EXACT));
LogFile << pretty_pv(pos, current_search_time(), Iteration,
TM.nodes_searched(), value, type, ss[0].pv) << endl;
}
if (value > alpha) if (value > alpha)
alpha = value; alpha = value;
} }
@ -1010,7 +968,7 @@ namespace {
{ {
cout << "info multipv " << j + 1 cout << "info multipv " << j + 1
<< " score " << value_to_string(rml.get_move_score(j)) << " score " << value_to_string(rml.get_move_score(j))
<< " depth " << ((j <= i)? Iteration : Iteration - 1) << " depth " << (j <= i ? Iteration : Iteration - 1)
<< " time " << current_search_time() << " time " << current_search_time()
<< " nodes " << TM.nodes_searched() << " nodes " << TM.nodes_searched()
<< " nps " << nps() << " nps " << nps()
@ -1021,7 +979,7 @@ namespace {
cout << endl; cout << endl;
} }
alpha = rml.get_move_score(Min(i, MultiPV-1)); alpha = rml.get_move_score(Min(i, MultiPV - 1));
} }
} // PV move or new best move } // PV move or new best move
@ -1186,7 +1144,7 @@ namespace {
// if the move fails high will be re-searched at full depth. // if the move fails high will be re-searched at full depth.
bool doFullDepthSearch = true; bool doFullDepthSearch = true;
if ( depth >= 3*OnePly if ( depth >= 3 * OnePly
&& !dangerous && !dangerous
&& !captureOrPromotion && !captureOrPromotion
&& !move_is_castle(move) && !move_is_castle(move)
@ -2574,6 +2532,36 @@ namespace {
} }
// print_pv_info() prints to standard output and eventually to log file information on
// the current PV line. It is called at each iteration or after a new pv is found.
void print_pv_info(const Position& pos, SearchStack ss[], Value alpha, Value beta, Value value) {
cout << "info depth " << Iteration
<< " score " << value_to_string(value)
<< ((value >= beta) ? " lowerbound" :
((value <= alpha)? " upperbound" : ""))
<< " time " << current_search_time()
<< " nodes " << TM.nodes_searched()
<< " nps " << nps()
<< " pv ";
for (int j = 0; ss[0].pv[j] != MOVE_NONE && j < PLY_MAX; j++)
cout << ss[0].pv[j] << " ";
cout << endl;
if (UseLogFile)
{
ValueType type = (value >= beta ? VALUE_TYPE_LOWER
: (value <= alpha ? VALUE_TYPE_UPPER : VALUE_TYPE_EXACT));
LogFile << pretty_pv(pos, current_search_time(), Iteration,
TM.nodes_searched(), value, type, ss[0].pv) << endl;
}
}
// init_thread() is the function which is called when a new thread is // init_thread() is the function which is called when a new thread is
// launched. It simply calls the idle_loop() function with the supplied // launched. It simply calls the idle_loop() function with the supplied
// threadID. There are two versions of this function; one for POSIX // threadID. There are two versions of this function; one for POSIX